Anyone working in air freight today would be amazed at the sight of loose cargo being loaded onto an aircraft, as was the case at the birth of the industry in the early 1900s. That might have worked when only a few bags were shoved into the hold, but not anymore, as increasing air freight volumes need to be contained in a unit load device (ULD) to both maximise use of space and protect the cargo.
And while most airlines rely heavily on pallets, air cargo would not exist without the huge range of containers flying around the world. There are, in fact, some 16 different container types and sizes, ranging from the most popular AKE (also known as the LD-3), which has a 4.3 cubic metre capacity, to the much smaller models such as the APA/DPA (LD-2), with a 3.4 cubic metre capacity, or the giant AWC (LD-6), which has 8.9 cubic metres of space.
Special containers are available for specific purposes, too. These may be walk-through, with doors at either end to allow loading from both sides; ‘flyaway’, to hold spare parts for the aircraft; transparent, to enable users to check that no goods have been left inside – ideal for carrying mail, since it is easy to leave an enveloped behind; or temperature-controlled, for perishable cargoes.
In fact, there are so many different container types that the International Air Transport Association (IATA) has issued standards to ensure airworthiness and guidelines advising how to store, load and handle each ULD.
IATA’s advice covers just about everything imaginable, including how ULDs should be stored; how they should be handled by forklifts – and how not; and how they should be marked to show their certification, or lack thereof. And that’s only a fraction of IATA’s requirements but, as it points out, the industry suffers from costly delays due to unavailability of suitable equipment and staff, the latter sometimes the result of injuries caused by improper handling of ULDs.
One of the difficulties in dealing with containers is their weight. The average traditional aluminium ULD weighs between 85 and 90 kilos, which means significant fuel usage, cost and carbon emissions. The huge rise in fuel prices has encouraged airlines to look for lighter weight alternatives and manufacturers are rising to the challenge. Nordisk Aviation Products and Driessen Air Cargo Europe, the two main producers of air freight containers, are both investing in newer, lighter materials.
“The first way to reduce weight is to take out some of the aluminium by reducing the depth of the base sheet,” explains Bart van Berkel, sales and marketing director of Driessen, now part of Zodiac Aerospace. “The minimum depth is now just 2.5-2.7 mm thick, but we can’t make it any thinner or it will wear out too quickly.
“In 2005, with the big demand in the industry to reduce weight further, we developed a composite material we call Herculight, made up of polypropylene and fibreglass. But over the last three years there has been even more demand from airlines to reduce the weight of anything on the aircraft.
“The only thing we could do was remove more aluminium from the container. We reviewed the design with our technicians and various industrial bodies to come up with something that removed aluminium without affecting the strength of the unit. Our newest container weighs just 60 kilos – and has been certified by the European Aviation Safety Agency (which means it is also approved by the US Federal Aviation Administration). We believe we have reached the lowest point possible without having an impact on durability, but we are working on yet another new design.”
Nordisk Aviation has spent a lot of its resources examining new material which supports its aim of providing safe, light, durable ULDs. But its preferred solution is Kevlar, a fibre developed from polymers by Dupont. “We have focussed on developing lightweight ULDs for several years,” says president Frode Ljoterud. “By using Kevlar, we can produce a container weighing just 55 kilos. The container comprises an aluminium frame with panels made from Kevlar.”Kevlar is twice as expensive as other materials, but if you look at the total cost of ownership and return on investment, it is very cost-effective. An ordinary ULD has to be repaired 2.5-3 times per year, whereas a Kevlar container only needs a maximum of two repairs. Damage is a huge issue, and Kevlar is stronger and less prone to damage.”
Nordisk has ULDs made from other composite material, too. It tried Dyneema, another fibre fabric, this time made from ultra-high molecule weight polyethylene, claimed to be 15 times stronger than steel. “We put Dyneema in a door and it is the strongest door we have,” confirms Ljoterud. “But if you compare it with Kevlar, looking at cost and weight differential, it does not make sense to switch to Dyneema.”
Yet another type of lightweight ULD is manufactured by Cargocomposites. Its AeroBox uses AeroPlaz composite panels, made from fibreglass/polypropelene skins, sandwiched with a unique honeycomb layer. A patented process closes and strengthens the panel edges in a way that enables the walls of the ULD to be connected with standard lock bolts, thereby eliminating the need for a damage-prone post and beam framework.
Lightweight ULDs are becoming the norm. Jettainer, a ULD management company, has tested a number of lightweight units. CHEP, the pooling company, will only buy lightweight units. CHEP is also testing fibre ULDs at its innovation centre in Orlando.
Cool technology
New developments have also been introduced for temperature-controlled containers. In 2005, Envirotainer introduced generator compressor cooling technology, which it calls the second generation of temperature-controlled ULDs. “It works like a fridge, comprising a liquid system, compressor, evaporator and condenser,” explains Nicholas Martin, director of research and development and quality assurance.
“This technology has a wider temperature range than dry ice. Dry ice is totally dependent on the outside temperature. The new container can maintain the internal temperature at a constant level, even if that means heating the ULD. If, for example, cargo must be kept at 15-25 degrees and the ULD is on the ramp at Heathrow for two hours in late December, the temperature of a dry ice container would drop below 15 degrees; the newer unit wouldn’t.
“Alternatively, if a product needs to be kept at 20 degrees, it can be hard to achieve that without a temperature-controlled hold, or a suitable ULD.”
Envirotainer provides two compressor-technology ULDs, the pallet-sized RKNe1 and the RAPt2, which can take up to five Europallets. Demand for these units is increasing by at least 5-10 percent a year, but this demand comes almost solely from the pharmaceutical sector. Compressor technology is a lot more expensive than dry ice.
Lufthansa is going for a similar market with its Opticooler ULD, launched two years ago using similar technology. Developed for the airline by Dokasch, Opticooler ULDs record the internal temperature of the cargo throughout the entire transport operation, making it easier for Lufthansa to help its customers comply with increasingly strict regulation.
Skycooler, another temperature-controlled ULD supplier, still relies on dry ice. “We made the decision not to go into the electrical ULD market because it would require a huge investment and because dry ice allows users to carry a variety of cargoes – meat and fish, fruit and vegetables, plants and flowers – as well as pharmaceuticals,” says CEO Jorgen Veslov.
“Our containers are made for us by the Dutch manufacturer VRR. They weigh a little more, but we designed them with a single door, rather than two, which helps prevent leakage. A built-in computer records the temperature for up to 96 hours and stores the data on board for up to one year.”
Skycooler, like Envirotainer, only leases its containers. Ambient ULDs are leased or purchased by the airline, or obtained from a pool. “Two years ago, we saw more leasing customers,” notes Maurice van Tarheijden, director EMEA (Europe, Middle East and Africa) at ACL Airshop, which supplies ULDs on a lease or sale basis. “We think leasing will increase further as airlines don’t want to invest in containers.”
Jettainer calls itself a service company for ULD management outsourcing, although it also offers short-term leasing. “Most customers lease from us,” explains Martin Kraemer, head of marketing and PR.
“ULD management is very niche for the cargo department, but has a huge impact. It is not the airline’s core business, but it is ours: we have experienced, dedicated staff only concerned with ULD management and an IT system developed in-house to help ensure we remain extremely efficient.”
Jettainer, which has 90,000 ULDs, a third of them containers, matches any new customer’s network to its existing network. “Because we have a global reach, we already serve at least 75 percent of the customer’s network. We work out the minimum and maximum number of each container type required at each station, depending on load factor, type of aircraft, flight frequency, route and so on, and can move ULDs around to ensure we stay within those requirements. An airline managing its own fleet often doesn’t even know how many ULDs it needs or has in each place.”
CHEP works on a different premise. It is, says president Dr Ludwig Bertsch, the only ULD pooling company in the world “We run a fleet of over 45,000 ULDs, 40 percent of which are containers, for approximately 25 airlines. We have our own brand and our own IATA code. Airlines pay a fixed rate per ULD per month. We also offer container repair and short-term leasing, where required.
“Airlines like having a fixed price,” adds Bertsch. “And they can adjust their stock on a monthly basis. If they axe a freighter, they tell us and we drop the number of units we provide. If they introduce a new route, we increase them. Our Bangkok operations centre has nearly 100 people whose only job is to manage ULDs, track and trace them and ensure they are at the right station at the right time. No airline could match that.”
Companies like Airshop, Jettainer and CHEP have the resources to work with manufacturers on new designs, to test new materials and help their customers get the best value out of their container fleet. It’s one way to approach the often overlooked equipment that is so vitally important for any cargo operation.
BOX: Airlines approach to ULDs
Air New Zealand and Cathay Pacific both own their own fleet of ULDs. Air New Zealand relies primarily on pallets, but these include the AAF, a pallet with a container on top. “We get more volume in that space,” says Finlay MacArthur, regional cargo manger for the UK. “We do have some containers, all of which we buy and maintain.”
Air New Zealand has tried out some lightweight units, both fibreglass and Kevlar-based. “It’s beneficial if you can make the ULD lighter,” says MacArthur, “but it still has to be strong enough to protect the cargo.”
Cathay Pacific has a fleet of around 8500 AKEs, as well as some other ULD models. It leases specialised units, such as temperature-controlled containers, and to cover peaks in traffic. “Container management is a key issue,” admits Peter Langslow, general manager, “particularly during passenger peaks when we get more luggage. We can average 44 AKEs in a B777, but during peak periods we may have to offload some. Making sure the right units are in the right place becomes more difficult.
“We are also concerned about the weight of a container. The new lightweight ULDs weigh around 60 kilos, compared to around 100 for a traditional unit. Multiply that by the number of units in one of our bellies – or a freighter – and you can soon see how much we can save on payload, fuel and cost.”
Lufthansa Cargo gets its ULDs from Jettainer, which forms part of the same group. “Our overall goal is to have a ULD delivered to the right place on time in good condition and at the right cost,” says Mrs Tony Schmidt, head of production support service. “This isn’t easy: we use 40 ULD types, but not all of them at every station at the same time!”
Schmidt claims Lufthansa Cargo has achieved almost 100 percent availability of units through the use of Jettainer, but it also borrows units from other carriers in emergencies. It also works with Jettainer to test new designs and materials. “We are pushing suppliers to investigate new technology, as there has been no progress in the development of new designs over the last couple of years,” Schmidt reports.
